1. Volume 24, Issue 2, Pages R60-R61 (January 2014)
Trade-offs 
Theodore Garland 
Current Biology 
Volume 24, Issue 2, Pages R60-R61 (January 2014)
DOI: /j.cub
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2. Figure 1
Grade shifts.
Two traits may be positively related among a phylogenetically diverse collection of species (left) (such as vertebrates), but (middle) negatively related when comparisons are made within sets of more closely related species (right) (subclades, such as salmonid fishes or passerine birds).
Current Biology  , R60-R61DOI: ( /j.cub )
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